[ARC5] Usage of large command set racks?

[Mike Morrow]

Mike wrote:

Strangely enough, the FT-* and MT-* racks have different junction boxes 
on the rear.  The ARC-5 version uses a single long box, while the 
SCR-274N version essentially pieces together two dual transmitter or 
receiver racks, along with their separate boxes, using 3/8" tubing to 
connect the two. 

There's another subtle mechanical difference between the AN/ARC-5 receiver racks and the ARA or SCR-274-N equivalents.  There is a lockwire anchor point on either side of the A/B audio select switches on the front of the AN/ARC-5 racks to allow the switches to be lockwired in position.  That was necessary since simplified AN/ARC-5 receiver control boxes did not have a A/B select switch.  The local rack switches were used to align the receiver audio output properly.  The *R-4/ARR-2, when included, was normally aligned to the A-bus, and all other receivers in the rack to the B-bus.

The early single receiver rack *MT-7/ARR-2 did not have an A/B select switch.  A dummy plug *MX-2/ARR-2 installed at the rear of the rack aligned the audio to the A-bus.  The later MT-7A had a A/B switch.

Mike / KK5F